1. Stress responses/stress avoidance
Plan C
We will pick a problem in plant biology and see where it takes us.
Plant products
Climate/CO2 change
Stress responses/stress avoidance

2. Stresses Chosen
Climate change
Temperature
Increased pCO2
Drought pH
Nutrient deprivation
Metal toxicity (a result of low pH)
Predation
Shaking

3. Friday
Present a plant stressor, what is known about it, and why it might affect plant 2˚ compounds in an ~ 10 minute presentation.
Alternative: present another good plant/stressor response to study and why we should choose it over the ones already chosen.

4. John Austin:
Jared Nicholoff:
Maria Chinikaylo:
David Pupaza: Fungal attack
Cassia Cole:
Kyle Schimmel:
Christina Gambino: Drought
Nathan Seabridge:
Andrew Hasuga:
Kenneth Werkheiser:
Kelvin Mejia:
Matt Yatison: UV radiation
Alexis Morgan:
Michael Yucha:
Catherin Morocho:
Atrazine? Cold? Shaking?Nutrient deprivation? Bact?
Ozone? Smog? Heavy metals? Predation?Heat?
Tom Nawrocki:

5. N assimilation by non-N fixers
Nitrate reductase in cytoplasm reduces
NO3- to NO2-
NO3- + NADPH = NO2- + NADP+
large enzyme with FAD & Mo cofactors
NO2- is imported to plastids & reduced
to NH4+ by nitrite reductase

6. S assimilation
Most cysteine is converted to
glutathione or methionine
Glutathione is main form
exported
Also used to make many other
S-compounds
Methionine also has many uses
besides protein synthesis

7. Natural Products
1˚ metabolites are essential for growth & development
therefore present in all plants
2˚ metabolites “not” required for growth & development
therefore not present in all plants
Often only found
in one or a few spp.
Derived from 1˚
metabs

8. Natural Products
2˚ metabolites not present in all plants
Often only found in one or a few spp.
Derived from 1˚ metabs, can be hard to draw line
Can be up to 3% of dry weight: very expensive to the the plant!

9. Natural Products
>100,000 types; tremendous variety of functions
Defense
Attractant
Protecting from UV
metal uptake and transport
Hardening cell walls

10. Natural Products
>100,000 types; 3 main groups
Terpenoids
Alkaloids
Phenolics

11. Natural Products
>100,000 types; 3 main groups
>30,000 terpenoids: made from isoprene units

12. Natural Products
>100,000 types; 3 main groups
>30,000 terpenoids: made from isoprene units
Some with N, most w/o
Monoterpenoids
mostly essential oils

13. Natural Products
>100,000 types; 3 main groups
>30,000 terpenoids: made from isoprene units
Some with N, most w/o
Monoterpenoids
mostly essential oils
Longer ones have
diverse functions
Pigments
Signals
Defense

14. Natural Products
>100,000 types; 3 main groups
>30,000 terpenoids: made from isoprene units
Longer ones have diverse functions
Pigments
Signals
Defense
Phytoecdysterones mimic
ecdysone & cause molting

15. Natural Products
>100,000 types; 3 main groups
>30,000 terpenoids: made from isoprene units
>12,000 Alkaloids: derived from amino acids: contain N

16. Natural Products
>100,000 types; 3 main groups
>30,000 terpenoids: made from isoprene units
>12,000 Alkaloids: derived from amino acids: contain N
Many drugs!

17. Natural Products
>100,000 types; 3 main groups
>30,000 terpenoids: made from isoprene units
>12,000 Alkaloids: derived from amino acids: contain N
Many drugs! Mainly for defense.

18. Natural Products
>100,000 types; 3 main groups
>30,000 terpenoids: made from isoprene units
>12,000 Alkaloids: derived from amino acids: contain N
>8,000 phenolics: contain phenol ring

19. Natural Products
>100,000 types; 3 main groups
>30,000 terpenoids: made from isoprene units
>12,000 Alkaloids: derived from amino acids: contain N
>8,000 phenolics: contain phenol ring
Crucial for moving onto land! Strengthen cell wall enough to support wt on land & transport water

20. Phenolics
>8,000 phenolics: contain phenol ring
Crucial for moving onto land! Strengthen cell wall enough to support wt on land & transport water
Comprise ~40% of organic C in the biosphere (most in cell walls)

21. Phenolics
>8,000 phenolics: contain phenol ring
Crucial for moving onto land! Strengthen cell wall enough to support wt on land & transport water
Comprise ~40% of organic C in the biosphere (most in cell walls)
Many serve other functions:
Pigments

22. Phenolics
>8,000 phenolics: contain phenol ring
Crucial for moving onto land! Strengthen cell wall enough to support wt on land & transport water
Comprise ~40% of organic C in the biosphere (most in cell walls)
Many serve other functions:
Pigments
Signals

23. Phenolics
>8,000 phenolics: contain phenol ring
Crucial for moving onto land! Strengthen cell wall enough to support wt on land & transport water
Comprise ~40% of organic C in the biosphere (most in cell walls)
Many serve other functions:
Pigments
Signals
Defense

24. Phenolics
>8,000 phenolics: contain phenol ring
Most are derived from phenypropanoid

25. Other natural products
~ 100 cyanogenic glycosides
Release cyanide when plant is damaged
Found in seeds of apricots, cherries, other fruits
Laetrile

26. Other natural products
> 100 glucosinolates: contain S and N

27. Other natural products
> 100 glucosinolates: contain S and N
Mainly found in Brassicaceae (crucifers)

28. Other natural products
> 100 glucosinolates: contain S and N
Mainly found in Brassicaceae (crucifers)
Made from modified amino acids bonded to glucose

29. Other natural products
> 100 glucosinolates: contain S and N
Mainly found in Brassicaceae (crucifers)
Made from modified amino acids bonded to glucose
Function in defense

30. Other natural products
> 100 glucosinolates: function in defense
When damaged release
Isothiocyanates
nitriles and elemental sulfur
Thiocyanates
oxazolidine-thiones
epithionitriles

31. Other natural products
The genus Allium produces sulfoxides derived from cysteine

32. Other natural products
The genus Allium produces sulfoxides derived from cysteine
When plants are damaged they are converted to pungent volatiles

33. Seeds
Seeds are unique feature of plants

34. Seeds
Seeds are unique feature of plants
Plant dispersal units

35. Seeds
Seeds are unique feature of plants
Plant dispersal units
Must survive unfavorable
conditions until they reach
suitable place (and time) to
start next generation

36. Seeds
Seeds are unique feature of plants
Plant dispersal units
Must survive unfavorable conditions until they reach
suitable place (and time) to start next generation
Are dormant

37. Seeds
Seeds are unique feature of plants
Plant dispersal units
Must survive unfavorable conditions until they reach
suitable place (and time) to start next generation
Are dormant; dehydration is key

38. Seeds
Seeds are unique feature of plants
Plant dispersal units
Must survive unfavorable conditions until they reach
suitable place (and time) to start next generation
Are dormant; dehydration is key
Germinate when conditions are right

39. Seeds
Germinate when conditions are right
Need way to sense conditions while dormant

40. Seeds
Germinate when conditions are right
Need way to sense conditions while dormant
Need reserves to nourish seedling until it is established

41. Seeds
(Usually) required for fruit development!

42. Seeds
(Usually) required for fruit development!
Role of fruit is to aid seed dispersal!

43. Seed Development
(Usually) required for fruit development!
Role of fruit is to aid seed dispersal!
Unfertilized flowers don’t develop fruit

44. Seed Development
(Usually) required for fruit development!
Role of fruit is to aid seed dispersal!
Unfertilized flowers don’t develop fruits
The growth regulators GA, auxin or cytokinin can all induce parthenocarpy

45. Seed Development
(Usually) required for fruit development!
Role of fruit is to aid seed dispersal!
Unfertilized flowers don’t develop fruits
The growth regulators GA, auxin or cytokinin can all induce parthenocarpy
GA + auxin or GA + cytokinin work best

46. Seed Development
(Usually) required for fruit development!
Role of fruit is to aid seed dispersal!
Unfertilized flowers don’t develop fruits
The growth regulators GA, auxin or cytokinin can all induce parthenocarpy
GA + auxin or GA + cytokinin work best
Hormones from embryo stimulate fruit development

47. Seed Development
Hormones from embryo stimulate fruit development
Other floral organs make inhibitor that blocks fruit development until they abscise

48. Seed Development
Hormones from embryo stimulate fruit development
Other floral organs make inhibitor that blocks fruit development until they abscise
Divide seed development into three phases of ± equal time

49. Seed Development
Divide seed development into three phases of ± equal time
Morphogenesis

50. Seed Development
Divide seed development into three phases of ± equal time
Morphogenesis
Maturation

51. Seed Development
Divide seed development into three phases of ± equal time
Morphogenesis
Maturation
Dehydration and dormancy

52. Seed Development
End result is seed with embryo packaged inside protective coat

53. Seed Development
End result is seed with embryo packaged inside protective coat
Seed coat is maternal tissue!

54. Seed Development
End result is seed with embryo packaged inside protective coat
Seed coat is maternal tissue!
Derived from epidermal tissue surrounding ovule

55. Seed Development
Seed coat is maternal tissue!
Derived from epidermal tissue surrounding ovule
Determines shape of the seed!

56. Seed Development
Seed coat is maternal tissue!
Derived from epidermal tissue surrounding ovule
Determines shape of the seed!
Testa mutants have odd-shaped seeds

57. Seed Development
Seed coat is maternal tissue!
Derived from epidermal tissue surrounding ovule
Determines shape of the seed!
Testa mutants have odd-shaped seeds
embryo grows to fill shape set by testa!

58. Seed Development
End result is seed with embryo packaged inside protective coat
Endosperm feeds developing embryo (3n grows faster)

59. Seed Development
End result is seed with embryo packaged inside protective coat
Endosperm feeds developing embryo (3n grows faster)
In many dicots endosperm is absorbed as seed develops

60. Seed Development
End result is seed with embryo packaged inside protective coat
Endosperm feeds developing embryo (3n grows faster)
In many dicots endosperm is absorbed as seed develops
Often leave a thin layer of endosperm just inside testa

61. Seed Development
End result is seed with embryo packaged inside protective coat
Endosperm feeds developing embryo (3n grows faster)
In many dicots endosperm is absorbed as seed develops
Often leave a thin layer of endosperm just inside testa
Seeds have three different genetic compositions!

62. Seed Development
End result is seed with embryo packaged inside protective coat
Endosperm feeds developing embryo (3n grows faster)
In many dicots endosperm is absorbed as seed develops
In many monocots
endosperm is seedling food

63. Seed Development
Embryogenesis
Maturation: cell division ± ceases, but cells still expand

64. Seed Development
Embryogenesis
Maturation: cell division ± ceases, but cells still expand
Controlled by different genes: viviparous mutants have normal morphogenesis but don’t mature

65. Seed Development
Embryogenesis
Maturation: cell division ± ceases, but cells still expand
Controlled by different genes: viviparous mutants have normal morphogenesis but don’t mature
Many morphogenesis mutants show normal maturation

66. Seed Development
Maturation: cell division ± ceases, but cells still expand
Activate new genes for making storage compounds

67. Seed Development
Maturation: cell division ± ceases, but cells still expand
Activate new genes for making storage compounds
ABA made by maternal tissue initiates this process

68. Seed Development
Maturation: cell division ± ceases, but cells still expand
Activate new genes for making storage compounds
ABA made by maternal tissue initiates this process
Seed [ABA] increases as enter maturation phase

69. Seed Development
Maturation: cell division ± ceases, but cells still expand
Activate new genes for making storage compounds
ABA made by maternal tissue initiates this process
Seed [ABA] increases as enter maturation phase
Switch to ABA synthesis by embryo & endosperm during maturation

70. Seed Development
Maturation: cell division ± ceases, but cells still expand
Activate new genes for making storage compounds
Storage compounds are key for seedlings and crops

71. Seed Development
Maturation: cell division ± ceases, but cells still expand
Activate new genes for making storage compounds
Storage compounds are key for seedlings and crops
Proteins, lipids & carbohydrates but vary widely

72. Seed Development
Maturation: cell division ± ceases, but cells still expand
Activate new genes for making storage compounds
Storage compounds are key for seedlings and crops
Proteins, lipids & carbohydrates but vary widely
Many 2˚ metabolites

73. Seed Development
Maturation: cell division ± ceases, but cells still expand
Activate new genes for making storage compounds
Storage compounds are key for seedlings and crops
Proteins, lipids & carbohydrates but vary widely
Next prepare for desiccation as ABA made by embryo (+endosperm) increases

74. Seed Development
Next prepare for desiccation as ABA made by embryo (+endosperm) increases
ABA peaks at mid-maturation, then declines (but not to 0)

75. Seed Development
Next prepare for desiccation as ABA made by embryo (+endosperm) increases
ABA peaks at mid-maturation, then declines (but not to 0)
Blocks vivipary during maturation

76. Seed Development
Next prepare for desiccation as ABA made by embryo (+endosperm) increases
Make proteins & other molecules (eg trehalose) that help tolerate desiccation

77. Seed Development
Next prepare for desiccation as ABA made by embryo (+endosperm) increases
Make proteins & other molecules (eg trehalose) that help tolerate desiccation
Next dehydrate (to 5% moisture content) and go dormant

78. Seed Development
Next dehydrate (to 5% moisture content) and go dormant
Very complex: 2 classes of dormancy
Coat-imposed
embryo dormancy

79. Seed Development
Coat-imposed dormancy (maternal effect)
Preventing water uptake.

80. Seed Development
Coat-imposed dormancy (maternal effect)
Preventing water uptake.
Mechanical constraint

81. Seed Development
Coat-imposed dormancy (maternal effect)
Preventing water uptake.
Mechanical constraint
Interference with gas exchange.

82. Seed Development
Coat-imposed dormancy (maternal effect)
Preventing water uptake.
Mechanical constraint
Interference with gas exchange
Retaining inhibitors (ABA)

83. Seed Development
Coat-imposed dormancy (maternal effect)
Preventing water uptake.
Mechanical constraint
Interference with gas exchange
Retaining inhibitors (ABA)
Inhibitor production (ABA)

84. Seed Development
Coat-imposed dormancy (maternal effect)
Preventing water uptake.
Mechanical constraint
Interference with gas exchange
Retaining inhibitors (ABA)
Inhibitor production (ABA)
Embryo dormancy (Zygotic effect)

85. Seed Development
Coat-imposed dormancy (maternal effect)
Embryo dormancy (Zygotic effect)
Making inhibitors (ABA?)

86. Seed Development
Coat-imposed dormancy (maternal effect)
Embryo dormancy (Zygotic effect)
Making inhibitors (ABA?)
Absence of activators (GA)

87. Seed Development
Coordinated with fruit ripening: fruit’s job is to protect & disperse seed
Seeds remain dormant until sense appropriate conditions:
some Lotus germinated after 2000 years!

88. Seed germination
Seeds remain dormant until sense appropriate conditions:
some Lotus germinated after 2000 years!
Water

89. Seed germination
Seeds remain dormant until sense appropriate conditions:
some Lotus germinated after 2000 years!
Water
Temperature: some seeds require vernalization = prolonged cold spell

90. Seed germination
Seeds remain dormant until sense appropriate conditions:
some Lotus germinated after 2000 years!
Water
Temperature: some seeds require vernalization = prolonged cold spell
May break down hydrophobic seed coat

91. Seed germination
Seeds remain dormant until sense appropriate conditions:
Water
Temperature: some seeds require vernalization = prolonged cold spell
May break down hydrophobic seed coat
May allow inhibitor (eg ABA) to go away

92. Seed germination
Seeds remain dormant until sense appropriate conditions:
Water
Temperature: some seeds require vernalization = prolonged cold spell
May break down hydrophobic seed coat
May allow inhibitor (eg ABA) to go away
May allow synthesis of specific RNAs

93. Seed germination
Seeds remain dormant until sense appropriate conditions:
Water
Temperature: some seeds require vernalization = prolonged cold spell
May break down hydrophobic seed coat
May allow inhibitor (eg ABA) to go away
May allow synthesis of specific RNAs
Many require light: says photosynthesis is possible

94. Seed germination
Seeds remain dormant until sense appropriate conditions:
Water
Temperature: some seeds require vernalization = prolonged cold spell
Many require light: says photosynthesis is possible
often small seeds with few reserves